Should I modify my SR4732A'a or leave them stock?

[Chris Davis]

Re: Should I modify my SR4732A'a or leave them stock?

Am I just getting tired and cross eyed or does it look like they run the 12's full range / all the way out in the full range passive mode in both the 4731 and 4732???

That sure does look like it, and is quite possible in real life. They just designed the speaker system around the "natural" frequency response of the woofer - rather than cram the woofer into the design. And also likely - they designed the woofer to do just that. A little bit less hacking that way. Then, as a fringe benefit, they are saving on a potentially large-gauge inductor (all the woofer current must flow through it on a LPF) and a cap.

 

[Royce Covington]

Re: Should I modify my SR4732A'a or leave them stock?

What's wrong with using the x-over from a 4731A & bypassing the 2404? They use the same components (4731 & 4732, same 2" horns and cone drivers) and both were designed and built by JBL. They should know what they're doing.

Yes, both were built by jbl and yes, they do know what they are doing, so, why try to change it?

I had used the 4732 for many years since they were introduced and don't remember them being 3-way. As I recall, the baby-butt simply added to the 2447 in the top-end, extending the range to 20k?

I have never had any problems while running the 4732's with adequate power. MA600/MA3600 for a pair and MA1200/MA5000 for two pair. The baby-butt failure is usually a sign of under-powered, over-driven use.

I'd just repair and use them as they were designed...

R~

 

[Mike Caldwell]

Re: Should I modify my SR4732A'a or leave them stock?

That sure does look like it, and is quite possible in real life. They just designed the speaker system around the "natural" frequency response of the woofer - rather than cram the woofer into the design. And also likely - they designed the woofer to do just that. A little bit less hacking that way. Then, as a fringe benefit, they are saving on a potentially large-gauge inductor (all the woofer current must flow through it on a LPF) and a cap.

The 2206 is fairly flat out to about 3k, granted that's on axis as there beaming like a spot light out that high! Like all things it was most likely a trade off is cost and performance as it would have taken some big inductors to allow for full power long term operation.

 

[Jeff Hague]

Re: Should I modify my SR4732A'a or leave them stock?

or biamp the cab and roll your own preset. Whatever you do, remove those baby butts and block off the hole. You'll save a little weight on an already heavy cabinet.

Just biamping those cabs wont "fix" it if the 2404s are blown because the xover between that and the 2447 is still in play...
I run 4732s over 4719s (-X, not As, the As may be different, I dont know). The 2404s blow way too easy and replacing diaphragms got real costly but biamping them didnt bring back the highs. I actually removed the crossovers altogether and they sound much better. It was a bit tricky figuring out the wiring to leave the original jack plate in place but remove the crossover. I do find that I have to boost the HF above about 12K.
Also, I run an XTi4000 on the 2206s and an XTi2000 on the 2447s and its plenty of power. An XTi1000 would likely work as well but the cost diff between the 2 isnt much and I figured Id rather have a little more power if I ever need to repurpose the amp.

 

[Tim Weaver]

Re: Should I modify my SR4732A'a or leave them stock?

Just biamping those cabs wont "fix" it if the 2404s are blown because the xover between that and the 2447 is still in play...
I run 4732s over 4719s (-X, not As, the As may be different, I dont know). The 2404s blow way too easy and replacing diaphragms got real costly but biamping them didnt bring back the highs. I actually removed the crossovers altogether and they sound much better. It was a bit tricky figuring out the wiring to leave the original jack plate in place but remove the crossover. I do find that I have to boost the HF above about 12K.
Also, I run an XTi4000 on the 2206s and an XTi2000 on the 2447s and its plenty of power. An XTi1000 would likely work as well but the cost diff between the 2 isnt much and I figured Id rather have a little more power if I ever need to repurpose the amp.

When I mentioned biamping, I was referring to removing the crossovers totally. Install an NL4 and make up your own presets. I realize that if you used the biamp input in the stock configuration HM/UHF would still go through the stock crossover. My bad for not clarifying...

 

[Gary Weller]

Re: Should I modify my SR4732A'a or leave them stock?

I do find that I have to boost the HF above about 12K.

Are you doing the boost on the xti's DSP or a GEQ? I'm planning on using a PEQ in the xti after running an RTA outdoors and seeing where I need to boost.

I also ordered a pair of 4731A x-overs and should have them next week. That way I can use them full-range until I get another amp to bi-amp them with.

Sucks working on a low budget.

 

[Jeff Hague]

Re: Should I modify my SR4732A'a or leave them stock?

Are you doing the boost on the xti's DSP or a GEQ? I'm planning on using a PEQ in the xti after running an RTA outdoors and seeing where I need to boost.

I also ordered a pair of 4731A x-overs and should have them next week. That way I can use them full-range until I get another amp to bi-amp them with.

Sucks working on a low budget.

Im using the DSP in the XTi. I first "copied" the JBL recommended presets from a DR260 into the XTi DSPs and then set it up outdoors and threw Smaart at it to get it dialed in.
Im actually using the XTi DSP for the house graphic too except when I have a guest engineer (not often) that wants a "real" one. Then I just insert one on the outputs of the console but leave the XTi settings in place.

 

[Gary Weller]

Re: Should I modify my SR4732A'a or leave them stock?

Im using the DSP in the XTi. I first "copied" the JBL recommended presets from a DR260 into the XTi DSPs and then set it up outdoors and threw Smaart at it to get it dialed in.
Im actually using the XTi DSP for the house graphic too except when I have a guest engineer (not often) that wants a "real" one. Then I just insert one on the outputs of the console but leave the XTi settings in place.

Are you using the preset from an SR4731 since you have bypassed the 2404?

 

[Jeff Hague]

Re: Should I modify my SR4732A'a or leave them stock?

Are you using the preset from an SR4731 since you have bypassed the 2404?

No. I always used the preset for the 4732 when I was using the DR and I figured that once I listened to it and looked at it with Smaart Id be messing up the HF output settings to compensate for the lack of the 2404anyway... I also raise the xover freq between the MF and HF from 1.2K (in the preset) to about 1.8K - I just dont like the sound of those horns below that. So even with the Driverack, I always treated the preset as just a good starting point.